Ces dernières années, l’intérêt porté à l'obtention de nouveaux systèmes catalytiques a connu un essor fulgurant. Ceci est lié, en particulier, aux applications industrielles variées qui s'étendent de la chimie fine à la chimie pharmaceutique. De nombreux catalyseurs ont ainsi été développés pour un nombre toujours croissant de réactions organiques. Néanmoins, la plupart des catalyseurs homogènes sont difficiles à adapter aux procédés industriels du fait de problèmes de séparation et de régénération. De plus, même efficaces, la plupart des catalyseurs contiennent des métaux nobles, coûteux et difficiles à recycler. C’est pourquoi, de nouveaux protocoles plus économiques et plus respectueux de l’environnement ont besoin d’être recherchés. L’utilisation de nanoparticules magnétiques comme support catalytique en synthèse organique représente une solution innovante pour répondre aux problèmes catalytiques rencontrés. Le but de ce travail consiste à concevoir des nano-catalyseurs magnétiques et à évaluer leur activité catalytique ainsi que leur recyclage pour des réactions de couplage carbone-carbone très utilisées en synthèse organique. Des nanoparticules de Maghémite synthétisées dans en milieux aqueux sont ensuite stabilisées en surface par des agents complexants possédant une fonction terminale qui permettra de les fonctionnaliser avec le catalyseur désiré (L- Proline, peptides, alcaloïde, Palladium). Ces nanomatériaux hybrides, constitués d'un cœur inorganique et d'une couche organique, ont été caractérisés par diverses techniques afin de déterminer leurs propriétés. Leurs activités ont été évaluées sur des réactions de couplage carbone-carbone modèles d'aldolisation, d'addition 1,4 de Michael et la réaction de Suzuki-Miyaura. / In the last decades, the interest for new catalysts and new catalytic reactions dramatically increased due to their miscellaneous industrial applications in fine or pharmaceutical chemistry for example. Lots of catalysts have been developed for an increasing number of organic reactions. Nevertheless, most of homogeneous catalysts are difficult to adapt to industrial process due to separation and regeneration problems. Furthermore, even if they are highly efficient, most of the catalysts contain noble metals often expensive and difficult to recycle. That’s why greener and much more economic protocols need to be developed. The use of nanoparticles as solid support for catalysts in organic chemistry appears as an innovative solution for solving these problems. Among the different inorganic nanomaterials, iron oxide nanoparticles represent an attractive tool due to their magnetic properties and easiness of obtaining. The aim of these work consist in designing magnetic nanocatalysts and evaluating their catalytically activity and recycling in C-C bond formation reactions which are commonly used in organic chemistry. Iron oxide nanoparticles (γ-Fe₂O₃) have been synthesized by soft chemistry in aqueous media. Particles have then been stabilized on surface by bidendate coating agents bearing a terminal function which enables post functionnalization with the desired catalyst (L-Proline, peptides, alkaloid, Palladium). These hybrids nanomaterials, with an inorganic core and an organic shell, have been characterized with various techniques in order to determine their properties. Catalysts activities have been evaluated on model C-C bond formation reactions such as aldolisation, 1, 4-Michael addition and cross coupling Suzuki-Miyaura cross coupling.

Historically, quantum dots (QDs) have generated tremendous excitement as a contrast agent, diagnostic tool, and even as a therapeutic in the 40 years since their discovery. Their brightness, narrow and tunable emission peaks, and large surface area for functionalization are all ideal properties for biomedical applications. However, there still are no clinically approved therapies utilizing QDs, and the toxicity of these systems have turned much of the excitement to disillusionment. In this thesis work, I outline some of the key barriers that have prevented QD translation to clinical settings — namely, proper toxicology assessment and bioaccumulation — and demonstrate some potential strategies to overcome these barriers. In the first aim, I show that copper indium sulfide (CIS, CuInS2) QDs are actually toxic, in contrast to previous literature that assumed non-toxicity. This result emphasizes how toxicity evaluation must be done carefully with proper separation of QD components (core, shell, and surface coating) that can influence or confound results. I also show that the toxicity of CIS QDs was linked to their degradation in vitro, highlighting the second barrier. In the second aim, I describe a novel, controlled synthesis of bornite (CuxFeS4) nanocrystals (NCs) with various Cu:Fe ratios and sizes and explore how those variables influence the optical properties of bornite. I also show the mechanism for the development of a localized surface plasmon resonance (LSRP) peak in bornite during oxidation, linking it to iron expulsion from the NCs and a subsequent rise in excess hole carriers. Finally, in my third aim I look at how copper iron sulfides are biodegradable, non-toxic, and useful for photothermal treatment. I demonstrate this premise through the selective lysis of bacterial cells using a NC-peptide platform that couples the targeting power of antimicrobial peptides with the photothermal capacity of bornite NCs.

Carbonized organic precursors such as wood, shells and some plant seeds are very porous. They are nanostructured and tend to be hard, but have pure mechanical properties as a result of their porosities. An attempt was made to carbonize an organic precursor to produce a bulk material with much less porosity for possible use in structural applications such as reinforcement in metal and polymer matrices. A bulk nanocarbon (BNC) material was synthesized using high energy ball milling and the carbonization of corn cob. Corn cob was mechanically milled for up to 20 hours by applying high energy ball milling to produce the milled powder. The milled powder was cold-compacted and carbonized at up to 1500°C to fabricate the BNC material. The material revealed both micro and nano-porosities; the porosities decreased with carbonizing temperature and hold time. Micropores were mostly closed for samples carbonized above 1300oC, whereas they formed interconnected network at lower carbonization temperatures. BNC has a young's modulus of 120 GPa, about ten times that of extruded graphite. / Master of Science / Wood, shells, and plant seeds are examples of organic precursors. When organic precursors are carbonized, they can become very porous, nanostructured, and hard, but deliver pure mechanical properties because of their porosities. A selected organic precursor was carbonized, in an attempt, to produce a bulk material with much less porosity for possible use in structural applications such as reinforcement in metal and polymer matrices. A bulk nanocarbon (BNC) material was made using high energy ball milling and the carbonization of corn cob (the selected organic precursor). This bulk material revealed both micro and nano-porosities, and a young's modulus of 120 GPa, about ten times that of extruded graphite.

The objective of this thesis was to investigate the suitability of some different Li4Ti5O12 materials as a negative electrode in hybrid supercapacitors. A hybrid supercapacitor is a combination of a battery and an electric double-layer capacitor that uses both a battery material and a capacitor material in the same device. The target for these combination devices is to bridge the performance gap between batteries and capacitors and enable both high energy and power density. To achieve this, materials with high capacity as well as high rate capability are needed. To improve the rate of the commonly slow battery materials nanosizing has been found to be an effective solution. This study shows that Li4Ti5O12 has a significantly higher experimental capacity than the most common capacitor material, activated carbon. The capacity remained high even at high discharge rates due to a successful nanostructuring that increased the accessibility of the material and shortened the diffusion distance for the ions, leading to a much improved power performance compared with the bulk material. The use of a nanostructured Li4Ti5O12 material in a hybrid device together with activated carbon was estimated to double the energy density compared to an electric double-layer capacitor and maintain the same good power performance. To further increase the energy density also improved materials for the positive electrode should be investigated.

Nanotechnology has been increasingly employed in forensic science for the detection of latent fingerprints, using multiple techniques from new aluminium nanomaterials for dusting to quantum dot dispersions, to try to increase and enhance areas where prints are likely to be found at scenes of crime. Different substrates use a diverse range of methods to develop prints when they are found and each method has its own drawbacks. It is not viable to use many of these techniques in conditions other than in a laboratory due to the harmful environmental effects they can cause over long term use. With this in mind a new easier to use technique that can be used on any substrate from wood to glass to paper was looked into. A range of nano-sized rare earth phosphor precursors were synthesised using homogeneous precipitation and solid state methods which were then converted to phosphors by firing at 980oC. Eu3+ and Tb3+ doped Y2O3, YVO4 and Y2O2S were chosen for their luminescent intensity. Analysis of each of the phosphors was carried out using multiple techniques and a single host lattice chosen for continuation. Y2O3:Eu3+ and Y2O3:Tb3+ were coated using a modified Stöber process to try and decrease the agglomeration of particles as well as allowing for surface modification to take place. Modifications of the surface were prepared and analysed, and these particles were then used in multiple fingerprint examinations to examine the adherence on fingerprints of different ages. The surface modifications manifested great adherence to the fingerprint residue even after two weeks elapsed and showed great promise after a two year period.

Nanomaterials have unique physics and chemistry properties compared with their bulk counterparts and have been widely studied in different fields ranging from energy to biomedicines. This thesis investigates controlled synthesis of gold nanomaterials, the heating and interactions of gold nanomaterials with external electromagnetic and ultrasonic fields, and their potential applications in non-invasive heat-related biomedicines. Gold nanomaterials have been synthesised by the citrate reduction method with the aid of ultrasonification. Through ultrasonification, the size of obtained spherical GNPs can be controlled between 10nm and 15nm, and the prepared nanoplates can be controlled between 50 nm to 150 nm. Purification process has been performed through membrane dialysis, in order to obtain pure nanoparticles for investigating the heating behavior of nanoparticle dispersions under EM/ultrasound field and elucidating the impurity effect. Moreover, the purified gold nanoparticles have been characterized by various means, such as FTIR, atomic absorption spectrometer, zetasizer, SEM, TEM and UV-Vis absorption for the purpose of fully understand the properties of gold nanoparticle in terms of purity, concentration, size, morphology and optical properties. The bulk heating effects of low-concentration GNPs have been investigated by using ultrasonic field, electromagnetic (EM) field, and laser irradiation. The results have shown that significant bulk temperature increase can be achieved for the lowconcentration gold nanoparticle dispersions under ultrasonic field, the EM field at 200 kHz and 400 kHz, and laser irradiation. Comparatively, the purified GNPs did not show significant heating effect under the EM fields of 13.56 MHz and 2.45 GHz. 6 Different mechanisms are thereby discussed to explain the heating effects. While some can be explained by established theories, such as the ultrasonic and laser heating, it is still unclear about the heating effect under low frequency EM field. A few possible reasons could be attributed to the changes of the dielectric properties and the electrophoresis effect. In addition, GNP incorporated microcapsules have been fabricated through the layer-bylayer technology, and laser treatments of the microcapsules embedded with different shapes of gold particles have been studied. The results have shown that matching between the laser wavelength and the absorption band of gold nanoparticles, which can be shifted by controlling the morphology of nanoparticles, is a prerequisite to achieve the maximum heating effect to deform the microcapsules and hence to present the microcapsules for biomedical uses. In vitro (B50 cell) and in vivo (fruit fly) studies of the biocompatibilities of our synthesised GNPs have been exanimated. The results demonstrated that the GNPs have high biocompatibility for B50 cells and fruit flies. GNPs assisted laser treatment of B50 cells has shown faster thermal damage to the cells in contrast to the cells without addition of GNPs. Keywords: nanomaterial, gold nanoparticle, capsules, hyperthermia, ablation, electromagnetic, ultraosound, surface Plasmon resonance, biocompatibility.

This dissertation is centered on investigation of metastable thermoelectric thin film materials and is split into 3 primary sections. Section 1 focuses on formation mechanisms of FeSbx compounds from layered precursors. It was found that a compositionally favorable and homogeneous nucleation environment allowed for the nucleation of a metastable phase, which surprisingly resembles the local coordination environment of the precursors, even in cases where they are compositionally unfavorable. Over the course of this work, the technique of normal-incidence thin film pair distribution function analysis is introduced, which allows for rapid acquisition and analysis of local structure data from intact thin films. Section 2 investigates changes in the stacking sequences of ([PbSe]1+δ)m(TiSe2)n nanolaminate materials, which consist of interleaved layers of each compound in the chemical formula, and how these changes effect the thermoelectric power factor. Homologous series of systematically varying m and n values are investigated and measured properties are correlated back to the designed nanoarchitecture of the laminate materials. It is found that the compounds are stabilized by electron exchange between constituents at the interfaces, and that ‘doping’ of the laminate structure by changing the relative amounts of each constituent is an effective means of optimizing their transport properties. It is also shown that interface density between constituents can be utilized to optimize performance. Section 3 moves from the case of PbSe layers, which maintain their structure, to SnSe layers that significantly distort as the layer size is changed. The distortions in SnSe are observed to occur from templating off TiSe2 layers. As the size of the SnSe layers increases, relatively fewer templated interfacial atoms exist and stabilization of interior atoms must also be considered. The coarse behaviors developed in ([PbSe]1+δ)m(TiSe2)n hold, but the structural distortions in SnSe likely change the band structure of this constituent and hence the composite material, complicating the analysis. In some cases, these changes allow for radically different behavior, best exemplified with high TiSe2 ratios in ([SnSe]1+δ)1(TiSe2)n displaying significant enhancement of the Seebeck coefficient at cryogenic temperatures over the low-n and PbSe-containing analogues. This dissertation includes previously published and unpublished coauthored material.

The production of engineered nanomaterials is an emerging and rapidly expanding industry. It exploits the capacity for materials to be manufactured to present particular properties distinct from the bulk material, through tailoring of the particle size and surface functionality. This ability to fine tune particle properties at the nanoscale is responsible for the explosion in uses of engineered nanomaterials in industries as diverse as cosmetics and medicine, to “green” technologies and manufacturing. However, this increased reactivity at the nanoscale, defined as having at least one dimension < 100 nm in size, is also responsible for the increasing concern over their environmental safety. Material flows of engineered nanoparticles into the aquatic environment have been identified throughout their production, use and disposal, putting these ecosystems at potential risk of contamination. In particular, sediments are a likely sink of engineered nanomaterials in the aquatic environment due to their propensity to destabilise and settle out of suspension in natural freshwaters. An emerging body of literature has demonstrated toxicity of nanomaterials to aquatic species. In this thesis, the case is presented for using bioaccumulation as a first indicator of risk to aquatic organisms exposed to engineered nanomaterials. Using the sediment dwelling freshwater worm, Lumbriculus variegatus, this work investigates the factors which govern the bioaccumulation of cerium oxide and silver nanomaterials. It is hypothesised that the fate of these materials in sediments will be determined by their core composition, primary particle size and surface coating. A novel approach is presented to measure two biologically relevant fate parameters (persistence of particles and dissolved species in the sediment pore waters) and how particle properties affect the distribution of the nanomaterials between these phases of the sediment. This provides the context within which to interpret biological exposures assessing both the extent of uptake and how they are accumulated, whether through dietary uptake or across the skin. Understanding this route to uptake is important as the mechanism of toxicity may depend upon the point of contact of a material at the nano-bio interface. For example, a nanoparticle which comes into contact with biological material in the gut may exert a different effect upon an organism than one which is translocated directly across the skin. It is demonstrated that sediment properties determine the fate of engineered nano cerium oxide and silver to a greater extent than stabilising surfactants, with the majority of particles aggregating or associating with the solid constituents of the sediment > 200 nm in size. The dissolved fraction of the metal present in the pore waters was a better predictor of bioavailability than the persistence of particulate material < 200 nm in size, with partially soluble nanosilver being more available than insoluble cerium oxide. The route to metal nanoparticle uptake also differed with particle core, with electrostatically stabilised citrate and sterically stabilised polyethylene glycol (PEG) coated ceria available only through dietary uptake, whilst citrate and PEG coated silver was accumulated through transdermal uptake. Dynamic changes in the fate of silver nanoparticles were also observed for sterically stabilised polyvinylpyrrolidone (PVP) coated silver, resulting in the emergence of a colloidal pore water fraction of silver after 3 months aging in sediments. However, this colloidal silver was still not considered accumulated, indicating that low molecular weight species of silver, dissolving from the particle surface either during the exposure or upon contact with the worms’ surfaces was responsible for uptake of silver from the sediments. In conclusion, this work contributes towards our understanding of the factors which determine both the route and extent of biological uptake of engineered nanomaterials. It presents a novel combination of methods which allow for understanding bioaccumulation of these materials in the context of their fate and behaviour within sediments.

No description available.

Two synthesis pathways were employed throughout this work to create a variety of unique carbon materials. The first of these routes involves the photo-dissociation of liquids by direct irradiation with ultrashort laser pulses; while the second entails the bombardment of polycrystalline chemical layers by a pulsed laser induced carbon plasma. The pulsed laser irradiation (PLI) of liquid benzene (C6H6) was found to result in the formation of amorphous carbon nanoparticles consisting of clusters of sp2-bonded aromatic rings bridged by sp hybridized polyyne functionalities. In a complimentary experiment, liquid toluene (C6H5CH3) was irradiated under similar conditions leading to the synthesis of a series of free floating methyl capped polyynes, with chain lengths ranging from C10 – C20. The synthesis of polyynes is an active and cutting edge topic in material science and chemistry. In a more complex experiment, solutions of ferrocene and benzene were irradiated by fs-laser pulses resulting in highly ordered mesoscale structures exhibiting four unique geometries; ribbons, loops, tubes, and hollow spherical shells. After a purification process, the higher order structures were destroyed and replaced with nanoparticles consisting of three distinct species including; pure iron, and two phases in which part of the ferrocene molecule was bound to either carbon or iron/carbon complexes. This material is extremely interesting because it exhibits properties similar to that of an electret and is also ferromagnetic over a large temperature range. In the final liquid phase laser irradiation experiment, a new hybrid deposition technique was originated and used to coat stainless steel electrodes with disordered mesoporous nanocrystalline graphite. This method involves the laser induced breakdown of benzene and the subsequent electrodeposition of the resulting carbon ions. Another focus in this work involved the synthesis of a special class of polymer-like carbon nanomaterials using a new method that augments traditional pulsed laser deposition. This technique involves the plasma processing of frozen materials with a pulsed laser initiated graphitic plasma. We call this technique "pulsed laser induced plasma processing" or "PLIPP". Various thin film compositions were created by processing alkane and alkene ices. Finally, in a slight departure from the previous experiments, the effects of carbon ion bombardment on water ice were examined in an effort to understand certain astrophysical processes.